could be like the nightingale he hears singing nearby, which would be another form of escape from himself and his unhappy thoughts. Finally in the fourth stanza he decides, since he has no wine, that he will escape in his imagination by creating a poem in which he actually flies to join the nightingale, and he succeeds in doing so.

Already with thee! tender is the night . . .

(F. Scott Fitzgerald used Keats' "tender is the night" as the title of his best novel.)

In stanzas 5, 6, and 7 he imagines what the world of the nightingale is like. At one point he mentions wine again:

    And mid-May's eldest child,
The coming musk-rose, full of dewy wine,
The murmurous haunt of flies on summer eves.

In the seventh stanza, his vivid imagination carries him far away. He says that the immortal song of the nightingale is the same song that has

Charm'd magic casements, opening on the foam
Of perilous seas, in faery lands forlorn.

He has succeeded--though only momentarily--in escaping from himself and his sorrows through poetry, but he cannot sustain the illusion he has created. The word "forlorn" first appears at the end of stanza 7 and then is repeated at the beginning of the eighth and last stanza.

Forlorn! the very word is like a bell
To toll me back from thee to my sole self!

The word "forlorn" sounds to him like the two notes of a clanging bell. A bell swings one way and the clapper strikes one side, sounding a dull tone. Then the bell swings back and the clapper strikes the other side, sounding a similar dull tone. Keats is using the imaginary sound of the bell to signal the beginning of the end of his poem and of his excursion into the world of the nightingale via his poetic imagination. He acknowledges that he does not have the power to escape permanently from his unhappiness through poetry. He says:

Adieu! the fancy cannot cheat so well
As she is famed to do, deceiving elf.

Perhaps the nightingale to whom he has been addressing his poem has started to fly away. He bids the immortal bird adieu and comes back to his senses and his sorrows, asking himself

Do I wake or sleep?

There is a "poetic conceit" running throughout the poem. He is pretending that the nightingale he hears singing in the shrubbery is immortal because, like most species of birds, it always sings the same notes, or the same "song." Immortality appeals to Keats because he is certainly dying and wishes it were not so. He is in love with a young girl but cannot marry her. He has dreams of writing many books of poetry but will never be able to complete them. The fact of death, at such an early age, is inescapable. He died in Italy not long after composing his poem to the nightingale he listened to in the garden.

The speaker wants to join the nightingale in the woods and forget his own troubles and sorrows. The speaker perceives the woods as a beautiful, tranquil place devoid of worries and death. In his view, the nightingale has it made. However, the speaker cannot shake his thoughts of a world where people grow older and sickly and lose their youth. He despises the idea of people growing older. The speaker seems obsessed with death, although he never mentions it directly. The enemy he identifies is thinking, which leads to sorrow and despair. For example, he knows every beautiful, young girl is going to lose her looks as she ages, and that red hot steamy love you found today inevitably will turn cold. This dude is dark and thinks dark. He would not be a great date unless you like brooding guys.

The lines you have quoted come from the first half of the last stanza of this famous Romantic poem, in which the speaker has a kind of out-of-body experience and reflects and meditates upon the human condition thanks to the song of the nightingale that he listens to. As the song of the nightingale ends, so the poet is brought back to earth, and this is what occurs at the beginning of this quote.

Note the use of the word "Forlorn." This is of course a word that is used in the previous line of hte poem, and the repetition underlines the speaker's mood and echoes the sound of the tolling bells that he compares it to, which calls the speaker back from his reverie to harsh reality. Although, in the middle of the poem, the "fancy" or imagination that is spoken of here is shown to operate in full power, transporting the speaker away from the trials and tribulations of life on earth, at the same time, the power of fancy and its limitations are indicated here, as the speaker refers to her as a "deceiving elf." The tone is one of reflective resignation as the speaker bids farewell to the "plaintive anthem" of the nightingale and is forced to rejoin reality.

You have quoted the last half of the final stanza of this famous Romantic poem, which describes how the speaker reurns to his senses after his out-of-body experience and becomes depressingly aware of the reality surrounding him as the sound of the nightingale's song fades away. As this music "flees" away, the speaker is left to question whether what he felt and experienced was a "vision, or a waking dream" and is left to ponder if he is actually asleep or awake as he comes out of his reverie.

Key to focus on in these final lines is the way that the tone in these final lines is reflective and resigned, due to the way in which the speaker clearly realises that there is no way to permanently escape his "sole self" and the suffering that forms such an intrinsic and inextricable part of the human condition. The speaker is left to grapple with the significance of his reverie and how he is altered as a result, or if he is altered at all. Having experienced the beauty of the nightingale's song, which seems to capture the eternal nature of beauty and poetry, he must come to terms with the fact that he does not dwell in this realm, and that he is transient.